Many previous studies of phonetic symbolism, wherein the sounds of a word convey the referent's attributes, have confounded multiple attributes such as size and shape. In the current study, participants viewed novel objects of varying size and shape and were asked to rate the appropriateness of a spoken non-word as a name for the object. Size and shape interacted (e.g., higher ratings were given for names with front vowels like /i/ when the object was small and spiky), and both spiky and round objects were phonetically marked. However, participants tended to use phonemes to mark size only when the object is large. This suggests that marking via phonemes should not be assumed to simultaneously mark all physical properties of the object (i.e., both size and shape). Consequently, phonetic symbolism of physical properties may not correlate as neatly with gesture as has previously been thought.